Multiple control



April 5, 1938. vw. A. rm 2,112,998

MULTIPLE CONTROL I Filed Sept. 26, 1936 'F 14 7 VI 4 r 4 -l l 72 v a 5 Z7 :Z6 2% I15 an? i L Z5 4' J4 J5 J6 0g] /6 /9 )2. 20 4/ 2/ v 22 4/ E Relay My) 5 Relq] Molar 7/ 0 46/ I} 4 69 9 INVENTOR.

/4/////7/77 ,4. Bay BY w M ATTORNEY.

Patented Apr. 5, 1938 MULTIPLE CONTROL William A. ltay, San Francisco, Calif., assignor to General Controls Company, a corporation of California lill catlon September 26, 1936, Serial No. 102,754-

scum.

This invention relates to the control of a conditioning unit by any one of a plurality of condition responsive devices to the end that one responsive device does not interfere with the operation of another responsive device. For example, the present invention makes possible the selective conditioning of various remotely located spaces. In accordance with this invention this selective conditioning of the remotely located spaces is effected without the condition of one space interfering with the. conditioning of another space.

It isin general the broad object to provide a suitable system permitting of the conditioning of a plurality of separate units such that the con ditioning of one unit does not aifect that of another.

Another object of the present invention is to provide a simple system for the separate control of a conditioning device by any one of a plurality of condition responsive devices.

The invention includes other objects and features of advantage, some of which, together with the foregoing, will appear hereinafter, wherein the present preferred systems of the invention are disclosed.

In the drawing, Figures 1 and 2 are diagram-' matic views illustrating systems incorporating I the principles of the present invention, and illus- 30 trating how it can be practiced.

Referring particularly to Figure 1,- I have shown aplurality of condition responsive devices' indicated by numerals ll, [2 and i3. Depending upon the use to which the present invention is intended to be put, these devices can be responsive to one or more of various conditions, such as pressure, temperature, humidity, viscosity or some other condition. In the presentcase, for purposes of discussion, .it is assumed that they are thermostats, and that the dotted line areas indicated as H, II and "surrounding each thermostat are room spaces to be maintained at certain desired temperatures.

45 Connected in series with each thermostat are a plurality of electric operators II, II and II for operating the solenoid operated valve elements in valves 2|, 2i and 22. The solenoid operators ll, ll and I! are each connected'in series with the associated thermostats H, I! and II, and asource of current, in this case alternating current, from lines 28 and It. Each solenoid operator is connected to its associated thermostat by a line 26 while each thermostat is connected to one side i a of the power line-by a line II, while the other raise the temperature therein.

(or. sic-1) side of the solenoid operator is connected by line 28 to the other side of the power line.

The valves 2., 2i and 22 are used, for example, to control the supply of steam, refrigerant or other conditioning medium to the associated spaces ll, l5 and It. Since the supplying of the associated conditioning iluid requires the operation of some other device such as a burner, a compressor motor, or a gas valve, means are provided for controlling operation thereof. In the 10 form illustrated in'the drawing, this includes an alternating current rectifier 3| connected by line 32 to one side of the alternating current source, in thiscase a 24 volt 60 cycle current. The other .slde of the rectifier is connected by line 3! and 15 lines a, 36 and it to each line 26. Upon a closing of each thermostat, current flows not only to the associated solenoid operators II, II and II, but to the rectifier as well.

for example, let us assume that thermostats i2 and it are'set to maintain temperatures of 68 deg. F. in their respective controlareas l5 and It, while thermostat ii is set to maintain a temperature of 72 deg. F. in associated control area ll. us assume the temperature in area It is 69 deg. F. Thermostat ll will then close, and current williiow through solenoid operator i1 and open valve 2| so that steam can flow intov the associated area II. [it the same time a current flows through line 34 and line 33 to rectifier ti and through line 32 to the alternating current source. The rectified current operates a sensitive relay, one utilizing about 0.02 watt, for example. This relay, indicated at 31, controls operation of a conditioning device 30 such as a 5 burner motor or a gas valve which controls the flow of fuel to a boiler, for example. The term motor is used as referring broadly to a conditioning device or a control element thereof as a burner motor or a gas valve. The boiler will generate 40 steam which can pass under the control of valve 2. through a radiator in space it, for example, to

The relay can control current flow to the motor through line it from power line 4..

In accordance with this invention, means are provided so that each one of the thermostats can selectively result in energization of the motor or other direct conditioning meansindicated by numeral 38. Thus Iinclude between line II and lines 34, 36 and It resistances ll. These resistances are so high that, for example, if solenoid operator II is energized, the other resistances will prevent the feeding back of suflicient current to operate solenoid operators II and It. I have found that resistances of the order of 800 ohms for the voltage indicated will usually suflice. Of course, this resistance is insuflicient to cut out all current feed back, but the-slight amount that does pass, of the order of 0.02 ampere, is insufficient to operate the solenoid operators l1, l8 and I9. As'a matter of fact, this slight feed back is desirable with solenoid type operators on alternating current for I have found that it results in demagnetization of the elements of the solenoid, effectively destroying the undesirable residual magnetism.

Therectifieremployed can be any one of the rectifiers now'well known, and I have successfully used the usual commercial type of copper oxide rectifier, although a thermionic tube rectifier can be used with success, although I find such a rectifier too expensive for commercial justification, since the present system must be sold competitively.

In Figure 2 I have shown the invention as applied to the control of a plurality of three wire motor operated controls 5|, 52 and 53. As iswell known, these controls are motor operated by a reversible motor, operation of the motor-in one direction serving to open a valve, for example, and in the opposite direction serving to close the valve. In this case, thermostats 54, 55 and 56 each includes a contact 51 which, when engaged by anoperating bar 58, serves to operate the motor in one direction, completing a circuit through lines 59, 60 and GI between the thermostat motor operated valve and the source of cur rent indicated by lines 62 and 63.

The thermostats include another contact 64, which,'when engaged, permits current to pass through lines 65 and 66 to operate the associated three wire motor valve in the opposite direction, and, at the same time, to permit current to pass through line 61 to complete a circuit through rectifier 3| controlling the sensitive direct current relay'3l, which in turn operates the conditioning device 38. In this case also resistances 68 are includes in series with the rectifier so that energization of one motor control by a thermostat does not result in energization of the remainder when current flows through the rectifier and back through line 69.

It will be obvious from the foregoing disclosure that devices l1, I8 and I9 and 5|, 52, and 53 can be utilized in combination with each other. For

solenoid operated valves from a source of alternating current, a motor, control means for said motor connected to each thermostat and to said current source including a current rectifier and a direct current relay operated thereby to control said motor, and a plurality of resistances interposed between each thermostat and said control means to prevent substantial current feed back to any other one of said solenoid operated valves.

2. In combination, a plurality of solenoid operated valves, a plurality of thermostats, each thermostat controlling current flow to one of said solenoid operated valves from a source of current common to all said solenoid operated valves, a motor, control means for effecting operation of said motor connected to each thermostat and to said common-current source, and a plurality of resistances interposed between each thermostat and said control means to prevent substantial current feed back to any other one of said solenoid operated valves upon closing of a circuit to said control means and one of said valves from said common current source.

3. In combination, a plurality of electrically operated control devices, a plurality of condition responsive devices, each condition responsive device controlling the supply of current to one of said control devices from a current source common to all said devices, a motor, a motor control device for eifecting operation of said motor connected to each of said condition responsive devices and to said current source, and means interposed between said motor control device and each of said condition responsive devices to prevent substantial current feed back to any other one of said control devices upon closing of a circuit to said control means and one of said control devices from said common current source.

WILLIAM A. RAY. 

